Mating system ofDatura inoxia: association between selfing rates and herkogamy within populations

Abstract

Plant mating system determines, to a great extent, the demographic and genetic properties of populations, hence their potential for adaptive evolution. Variation in plant mating system has been documented between phylogenetically related species as well between populations of a species. A common evolutionary transition, from outcrossing to selfing, is likely to occur under environmental spatial variation in the service of pollinators. Here, we studied two phenotypically (in floral traits) and genetically (in neutral molecular markers) differentiated populations of the annual, insect-pollinated, plant Datura inoxia in Mexico, that differ in the service of pollinators (Mapimí and Cañada Moreno). First, we determined the populations’ parameters of phenotypic in herkogamy, outcrossing and selfing rates with microsatellite loci, and assessed between generation (adults and seedlings) inbreeding, and inbreeding depression. Second, we compared the relationships between parameters in each population. Results point strong differences between populations: plants in Mapimí have, on average, approach herkogamy, higher outcrossing rate (tm = 0.68), lower primary selfing rate (r = 0.35), and lower inbreeding at equilibrium (Fe = 0.24) and higher inbreeding depression (δ = 0.25), than the populations of Cañada. Outcrossing seems to be favored in Mapimí while selfing in Cañada. The relationship between r and Fe were negatively associated with herkogamy in Mapimí; here, progenies derived from plants with no herkogamy or reverse herkogamy had higher selfing rate and inbreeding coefficient than plants with approach herkogamy. The difference Fe–F is positively related to primary selfing rate (r) only in Cañada Moreno which suggests inbreeding depression in selfing individuals and then genetic purging. In conclusion, mating system evolution may occur differentially among maternal lineages within populations of Datura inoxia, in which approach herkogamy favors higher outcrossing rates and low levels of inbreeding and inbreeding depression, while no herkogamy or reverse herkogamy lead to the evolution of the “selfing syndrome” following the purge of deleterious alleles despite high inbreeding among individuals.

Evolution of selfing syndrome and its influence on genetic diversity and inbreeding: A range‐wide study in Oenothera primiveris

“…This allowed for increased autogamous seed set (Opedal, 2018), elevating rates of self‐fertilization and levels of inbreeding, as has been seen in other species (e.g., Ipomoea lacunosa L., Duncan and Rausher, 2013a; Camissoniopsis cheiranthifolia , Dart et al, 2012; Arabis alpine Krock. ex Steud., Tedder et al, 2015; Linaria cavanillesii , Voillemot and Pannell, 2017; Datura inoxia Mill., Jiménez‐Lobato and Núñez‐Farfán, 2021; Mimulus guttatus species complex, Bodbyl Roels and Kelly, 2011).…”

Inbreeding in Chinese Fir: Insight into the Rare Self-Fertilizing Event from a Genetic View

“…The morphological traits that are expected to influence mating systems are known to be highly dynamic, varying widely among populations or individuals, and have been well documented in some species, such as Arabidopsis lyrata [ 10 , 11 ], Arenaria uniflora [ 12 ], the Leavenworthia species [ 13 , 14 , 15 ] and Eichhornia Paniculata [ 16 ]. The most frequent evolutionary shift of mating systems is the transition from outcrossing to selfing across the plant kingdom [ 4 , 17 , 18 ]. From the perspective of genetic consequences, selfing is expected to show reduced effective recombination rates and increased homozygosity, resulting in decreasing genetic diversity relative to outcrossing [ 19 , 20 ].…”